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Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

What is syndrome of inappropriate antidiuretic hormone secretion (SIADH)?

Although rare in children outside of the hospital, SIADH occurs when the body produces an excessive amount of antidiuretic hormone (ADH). This is a hormone that normally helps the kidneys conserve the correct amount of water. SIADH causes the body to retain water, which drops the blood sodium level.

What causes SIADH?

SIADH tends to occur in people with heart failure or people with a brain injury that affects the hypothalamus (the part of the brain that works directly with the pituitary gland to produce hormones). In adults, certain lung cancers may produce an ADH-like hormone. Other causes may include the following:

Meningitis (inflammation of the meninges, the membranes that cover the brain and spinal cord)

Encephalitis (inflammation of the brain)

Brain tumors

Psychosis

Lung diseases

Head injury

Guillain-Barré syndrome (a reversible condition that affects the nerves in muscle resulting in weakness, pain, and even temporary paralysis of the facial, chest, and leg muscles. Paralysis of the chest muscles can lead to breathing problems.)

Certain medications

Damage to the hypothalamus or pituitary gland during surgery

Thyroid or parathyroid hormone deficiencies

HIV

Hereditary causes

What are the symptoms of SIADH?

Each person may experience symptoms differently. In more severe cases, symptoms may include:

Nausea or vomiting

Cramps or tremors

Depressed mood or memory impairment

Irritability

Personality changes, such as combativeness, confusion, and hallucinations

Seizures

Stupor or coma

The symptoms of SIADH may look like other problems or medical conditions. Always consult your child's health care provider for a diagnosis.

How is SIADH diagnosed?

In addition to a complete medical history and physical exam, diagnosis of SIADH involves blood and urine tests to measure sodium, potassium, and osmolality (the overall concentration of substances dissolved in the blood and urine).

Treatment for SIADH

The most commonly prescribed treatment for SIADH is fluid and water restriction. If the condition is chronic, fluid restriction may need to be permanent. Treatment may also include:

Certain medications that inhibit the action of ADH (also called vasopressin)